The invention relates to a braking method and system for electrically powered or hybrid motor vehicles, and more particularly to decoupled braking methods and systems for electrically powered or hybrid motor vehicles.
The expression “decoupled braking” means braking without any direct mechanical link between the brake pedal and the braking device.
By contrast with a conventional braking system, therefore, a decoupled braking system allows the driver's action on the brake pedal to be dissociated from the deceleration that actually takes place.
Additionally, in an electrically powered or hybrid vehicle, braking can be provided by a brake actuator, such as a hydraulic actuator, or by an electric propulsion actuator which, in regenerative mode, enables electrical energy to be recovered, this energy being storable in batteries, thus increasing the range of the electrically powered or hybrid vehicle.
Furthermore, there are known devices for controlling the stability of motor vehicles.
However, regenerative braking may lead to stability problems for the vehicle, notably in emergency braking. There are also known motor vehicle stability modules, such as those disclosed in KR20090043 126 and US200260220453, in which the energy recovery function is deactivated solely in circumstances of antilock braking control (ABS).
WO200837347 describes a stability module which deactivates the energy recovery function in accordance with an electronic vehicle stability control system.
Reference may also be made to EP2055589 which describes an energy recovery method which does not take the stability of the vehicle into account.
There has also been a proposal, in US20050200197, to calculate the braking torque, within a system operating in open loop mode and using predetermined curves.
U.S. Pat. No. 6,155,365 describes a theoretical braking method which does not take the stability of the vehicle into account.